Cats Control Rats ... With Parasites

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Cats Control Rats ... With Parasites

That cat urine frightens rats is an elementary fact of rodent life. It doesn't even matter if they've never seen a cat; the forces of evolution have hard-wired it into their brains, leaving less fearful rats in their nemeses' bellies"

What, then, could attract rats to cat pee? None other than toxoplasma gondii, a parasite carried by cats. If a rat is infected by t. gondii, cat urine doesn't seem so bad anymore; it's even kind of attractive. Even more impressively, Stanford University researchers have found that the rats otherwise behave normally, with all their usual fears intact. The response is so specific that cats and *t. gondii *seem almost like a single organism – which, in a sense, they are.

When it jumps to rats – and, for that matter, to humans, in whom it's linked to schizophrenia – *toxoplasma gondii *goes right to the brain and concentrates in the amygdala, a region associated with fear. The next step is to determine exactly how t. gondii changes the brain, and to associate those changes with behavior.

The amazing evolution of analytical technologies: first microscopes, then magnetic resonance imaging, and now parasites.